CN107945237B - Multi-scale calibration plate - Google Patents
Multi-scale calibration plate Download PDFInfo
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- CN107945237B CN107945237B CN201711440906.5A CN201711440906A CN107945237B CN 107945237 B CN107945237 B CN 107945237B CN 201711440906 A CN201711440906 A CN 201711440906A CN 107945237 B CN107945237 B CN 107945237B
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Abstract
The invention discloses a multi-scale calibration plate, wherein at least two groups of calibration base points and identifiable codes are arranged on the surface of the multi-scale calibration plate; each group of calibration base points comprises at least three same calibration points which are distributed in an orthogonal relation; defining a first group of calibration base points as a group of calibration base points close to the edge of the multi-scale calibration plate and a second group of calibration base points as a group of calibration base points adjacent to the first group of calibration base points; the area of a single calibration point of the first group of calibration base points is larger than the area of a corresponding calibration point in the second group of calibration base points; the codes are arranged between at least one adjacent and nearest two calibration points in each group of calibration base points, and the codes of the groups of calibration base points are different from each other. The method is suitable for calibrating the imaging devices with different visual fields, avoids customizing calibration plates with different sizes and algorithms matched with the calibration plates, and saves the cost of hardware and development and maintenance.
Description
Technical Field
The invention relates to the technical field of computer vision, in particular to a multi-scale calibration plate.
Background
In the 4.0 industrial age, industrial automation technology has been rapidly developed. The machine vision technology is an important direction of industrial automation technology, and increasingly plays important roles in social production and life, such as vision monitoring, automatic part identification and measurement, three-dimensional reconstruction, terrain matching, medical image processing and the like. The imaging device is used as an important detection means in visual detection, and the importance of the calibration technology to computer vision is the same as that of scales to rulers.
In the previous calibration process, because the sizes of the tested products are different, the visual field sizes of the imaging devices matched with the visual system are different, and in order to improve the detection precision and reduce the cost to the maximum degree, a proper resolution imaging device and a proper lens are selected. Due to the fact that the view fields are different in size, calibration boards different in size and algorithms matched with the calibration boards need to be customized in the calibration process, hardware cost is increased, and development and maintenance cost is increased.
In addition, the adjustment and calibration of the initial state of the vision system are all operated manually, and besides repetitive operation and operation by skilled workers, errors caused by human factors cannot be avoided in the calibration result.
Disclosure of Invention
In view of the above problems, the present invention provides a multi-scale calibration board, which only needs one calibration board and automatically selects calibration base points with different calibration ranges on the calibration board to complete calibration according to the sizes of windows of different imaging devices, thereby reducing hardware cost and development and maintenance cost, and avoiding calibration errors caused by human factors.
According to one embodiment of the invention, a multi-scale calibration plate is provided, the surface of the multi-scale calibration plate is provided with at least two groups of calibration base points and identifiable codes;
each group of calibration base points comprises at least three same calibration points which are distributed in an orthogonal relation;
defining a first group of calibration base points as a group of calibration base points close to the edge of the multi-scale calibration plate and a second group of calibration base points as a group of calibration base points adjacent to the first group of calibration base points; the area of a single calibration point of the first group of calibration base points is larger than the area of a corresponding calibration point in the second group of calibration base points;
the codes are arranged between at least one adjacent and nearest two calibration points in each group of calibration base points, and the codes of the groups of calibration base points are different from each other.
In the multi-scale calibration plate described above, the calibration points are circles, ovals, squares, "+", "×" or triangles with fill colors.
In the multi-scale calibration plate, the codes between each set of calibration base points can be identified in multiple directions and correspond to the same identification result.
In the multi-scale calibration plate, the code is a bar code, a two-dimensional code, a number, a character or a geometric figure.
In the above multi-scale calibration plate, the code corresponds to at least one physical distance.
In the above multi-scale calibration board, the encoding includes an encoding start bit, an encoding bit, and an encoding end bit.
In the multi-scale calibration plate, the shape of the multi-scale calibration plate is circular, elliptical, square, triangular or polygonal.
In the multi-scale calibration plate, the calibration points and the codes are arranged on both sides of the multi-scale calibration plate.
In the above multi-scale calibration plate, the material of the multi-scale calibration plate may be a light-transmitting material or a backlight material.
Another embodiment of the present invention provides an adaptive calibration system, including:
the multi-scale calibration plate comprises at least two groups of calibration base points, wherein each group of calibration base points comprises at least three same calibration points which are distributed in an orthogonal relation; defining a first group of calibration base points as a group of calibration base points close to the edge of the multi-scale calibration plate and a second group of calibration base points as a group of calibration base points adjacent to the first group of calibration base points; the area of a single calibration point of the first group of calibration base points is larger than the area of a corresponding calibration point in the second group of calibration base points; the codes are arranged between at least one adjacent and nearest two calibration points in each group of calibration base points, and the codes of the groups of calibration base points are different from each other;
and the imaging device is used for acquiring the image data of the multi-scale calibration plate and processing the image data to finish the calibration process.
The multi-scale calibration plate of the invention at least provides the following technical effects: only one calibration plate is needed, calibration base points with different calibration ranges are fused in one calibration plate, the visual system with different visual field sizes can be compatible for calibration, the calibration plates with different sizes and algorithms matched with the calibration plates are avoided being customized, the hardware cost and the development and maintenance cost are saved, and meanwhile, calibration errors caused by human factors due to the fact that the calibration plates are repeatedly placed are avoided.
Drawings
In order to more clearly illustrate the technical solution of the present invention, the drawings required to be used in the embodiments will be briefly described below, and it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope of the present invention.
Fig. 1 shows a schematic structural diagram of a multi-scale calibration plate according to a first embodiment of the present invention.
Fig. 2 is a schematic diagram illustrating an application environment of an adaptive calibration system according to an embodiment of the present invention.
Fig. 3 shows a schematic flow chart of an adaptive calibration method according to an embodiment of the present invention.
Fig. 4 shows a schematic structural diagram of a multi-scale calibration plate according to a second embodiment of the present invention.
Fig. 5 is a schematic structural diagram illustrating encoding between two nearest neighboring calibration points in a multi-scale calibration board according to an embodiment of the present invention.
Fig. 6 shows a schematic structural diagram of a multi-scale calibration plate according to a third embodiment of the present invention.
Description of the main element symbols:
10-an imaging device; 12-multi-scale calibration plate; 121-index point; 122-encoding; 123-code start bit; 124-encoding end bit; 125-coded bits.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the multi-scale calibration plate is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
The following detailed description of embodiments of the invention refers to the accompanying drawings.
Example 1
Fig. 1 shows a distribution diagram of a multi-scale calibration plate according to an embodiment of the present invention. The multi-scale calibration plate 12 is provided with at least two sets of calibration base points 121 and identifiable codes 122 on the surface.
Each set of calibration base points 121 includes at least three identical calibration points distributed in an orthogonal relationship. In this embodiment, each set of calibration base points is illustrated by taking four calibration points in an orthogonal relationship as an example. In other embodiments of the present invention, each group of calibration base points may further include three or more than four calibration points, which form an orthogonal relationship with the connecting line of the center points of the calibration points at any angle.
Defining a first group of calibration base points as a group of calibration base points close to the edge of the multi-scale calibration plate and a second group of calibration base points as a group of calibration base points adjacent to the first group of calibration base points; the area of a single calibration point of the first set of calibration base points is larger than the area of a corresponding calibration point of the second set of calibration base points. For example, the first set of calibration base points includes four calibration points a0, B0, C0, D0, and the second set of calibration base points includes four calibration points a1, B1, C1, D1, wherein the center-to-center lines of a0, B0, C0, D0 are orthogonally distributed, and the center-to-center lines of a1, B1, C1, D1 are orthogonally distributed.
The sizes, the shapes and the structures of the four index points A0, B0, C0 and D0 are the same, and the sizes, the shapes and the structures of the four index points A1, B1, C1 and D1 are the same. The areas of the first group of calibration base points A0, B0, C0 and D0 are all larger than the areas of the second group of calibration base points A1, B1, C1 and D1.
The code 122 is disposed between at least one adjacent and nearest two of the calibration points of each set of calibration base points, the codes of each set of calibration base points are the same, and the codes of each set of calibration base points are different from each other. In this embodiment, the code 122 is disposed between two adjacent and nearest calibration points of each calibration base point, that is, one code 122 is provided. In other embodiments of the present invention, the number of codes 122 in each set of calibration base points is plural. For example, in the first set of base points A0, B0, C0, and D0, only the code is provided between the index points B0C0, and no code is provided between the index points A0B0, between the index points C0D0, or between the index points A0D 0. In the second group of calibration base points A1, B1, C1 and D1, only the codes are arranged between the calibration points B1C1, and no codes are arranged between the calibration points A1B1, between the calibration points C1D1 and between the calibration points A1D 1. The codes between the first set of calibration base points and the codes between the second set of calibration base points are different, i.e., the codes between the calibration points B0C0 and the codes between the calibration points B1C1 are different from each other and correspond to different physical distances.
Finally, it is within the scope of the present invention that one point participates in the calculation, for example, in the present embodiment, the pixel coordinates of the center point of the circular calibration point and the pixel distance between two center points need to be calculated to participate in the calculation of the subsequent calibration parameters, and other grid types, for example, require the pixel coordinates of the calibration point particles and the pixel distance between two particles to participate in the subsequent calculation.
In this embodiment, the code is a barcode in one mode, and can be recognized in multiple directions and obtain the same recognition result. For example, taking the barcode between the index points B1C1 as an example, the recognition results of the encoded information obtained by scanning in the C1 direction starting from the B1 position and the encoded information obtained by scanning in the B1 direction starting from the C1 position are completely the same; if the code is a two-dimensional code, scanning can be performed in four directions, namely, up, down, left, and back, and the same identification result can be obtained. In other embodiments of the present invention, the code may be a bar code, a two-dimensional code, a number, a character, or a geometric image in other ways. Such as the numbers "1", "2", "3", the characters "123 + abc", etc.
The shape and material of the multi-scale calibration plate 12 can be set according to actual requirements, for example, in the embodiment, the shape of the multi-scale calibration plate 12 is a square, and in other embodiments of the present invention, the shape of the multi-scale calibration plate can be a circle, an ellipse, a triangle, or a polygon. In the surface light system, a multi-scale calibration plate made of surface reflection materials can be placed; in a backlight system, a multi-scale calibration plate of light-transmissive material may be placed. The multi-scale calibration plate can be provided with the calibration points and the codes on two sides.
According to the multi-scale calibration plate, calibration base points in different calibration ranges are fused in one calibration plate, the calibration plate can be compatible with visual systems with different visual field sizes for calibration, the calibration plates with different sizes and algorithms matched with the calibration plates are prevented from being customized, the hardware cost and the development and maintenance cost are saved, and meanwhile, the calibration error caused by human factors due to the fact that the calibration plates are repeatedly placed is avoided.
Fig. 2 is a schematic diagram illustrating an application environment of an adaptive calibration system according to an embodiment of the present invention.
The application environment of the adaptive calibration system comprises an imaging device 10 and a multi-scale calibration board 12.
The imaging device 10 is used for acquiring image data, and may include a computer terminal integrated with a photographing function, such as a mobile phone, a tablet computer, a notebook, a desktop, and the like, having a camera function; it is also possible to include terminal equipment with a photographing function, such as a camera, a video recorder, a video camera, etc., and the imaging apparatus 10 and the computer terminal exist separately by way of connection. Wherein, the connection mode can be fixed connection, also can be detachable connection, or integrated connection; can be mechanically or electrically connected; the connection can be wired connection or wireless connection; the connection can be direct or indirect through an intermediate; there may be communication between the interiors of the two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
The multi-scale calibration board 12 is used for calibrating calibration parameters of the imaging device, and includes at least two calibration base points forming an orthogonal relationship, each calibration base point includes at least three same calibration points, a code is arranged between two nearest adjacent calibration points distributed in the orthogonal relationship between each calibration base point, and the codes of each group are different from each other.
The adaptive calibration system shown in fig. 2 does not constitute a limitation of the present invention and may include more or fewer components than shown, or some components in combination, or a different arrangement of components.
Fig. 3 shows a schematic flow chart of an adaptive calibration method according to an embodiment of the present invention.
In step S170, image data containing a multi-scale calibration plate is acquired.
For example, at least one set of calibration base points on the multi-scale calibration plate is included in the acquired image data.
In step S180, it is determined whether or not the image data includes a multi-scale calibration board.
And judging whether the acquired image data contains the multi-scale calibration plate or not, and advancing to step S190 under the condition that the image data at least comprises a group of calibration base points on the multi-scale calibration plate. If the image data does not include the multi-scale calibration board, the process proceeds to step S200.
In step S190, it is determined whether the multi-scale calibration plate data is suitable for measurement.
And judging whether the collected multi-scale calibration plate data is intact and suitable for measurement. That is, the image data containing the multi-scale calibration plate can completely and accurately identify the calibration point. In the case where the multi-scale calibration board data is intact, the process proceeds to step S210. In the case where the multi-scale calibration plate data cannot be accurately measured, it proceeds to step S200.
In step S200, a multi-scale calibration plate suitable for calibration is placed.
And (5) repositioning the multi-scale calibration plate suitable for calibration according to the factors such as the position and the integrity of the multi-scale calibration plate, and the like, advancing to the step S170, and calibrating the imaging device again.
The position, i.e. the image data captured by the imaging device, at least comprises a set of calibration base points on the multi-scale calibration plate. The completeness, namely the code between each group of calibration base points and each adjacent two closest calibration points on the multi-scale calibration plate is intact, and each group of calibration base points and the code between the same shot by the imaging device can be recognized by the computer terminal as the standard.
In step S210, a set of calibration base points with the largest area in the image data is acquired.
For example, an image is subjected to a binarization segmentation process, connected regions on the image data are identified,
and filtering the interference points and the connected regions adhered to the edges on the image data by adopting a morphological algorithm, calculating the areas of the rest connected regions on the image data, and acquiring a group of connected regions with the largest and equal areas in the rest connected regions as a group of calibration base points with the largest area on the multi-scale calibration plate.
The morphological algorithm is a relatively preferable image processing method, and does not limit the adaptive calibration method, and the same effect can be obtained by other image processing methods.
As shown in fig. 4, in the visual field Rect0, after filtering the interference points, the edge adhesion region and the non-connected region, a group of calibration base points with the largest area is obtained as a group of a0, a group of B0, a group of C0 and a group of D0; in the visual field Rect1, after filtering interference points, edge adhesion areas and non-communication areas, obtaining a group of calibration base points with the largest area, namely A1, B1, C1 and D1; in the visual field Rect2, after filtering the interference points, the edge adhesion area and the non-connection area, a group of calibration base points with the largest area is obtained as A2, B2, C2 and D2.
In step S220, it is determined whether the base points are the same set of calibration base points.
Whether the set of calibration base points are the same set of calibration points is determined according to the relative position relationship, the area, the shape and other factors of the set of calibration base points with the largest area obtained in step S210. If the set of calibration base points is the same set, the process proceeds to step S230. In the case where the set of calibration base points is not in the same set, the process proceeds to step S170 to re-perform the calibration process of the imaging apparatus.
As shown in fig. 4, if the group of calibration base points with the largest obtained area is a0, B0, C0 and D0, and a0, B0, C0 and D0 have the same area and shape and are distributed in an orthogonal relationship, it is determined that a0, B0, C0 and D0 are the same group of calibration base points; if the group of the base points with the largest obtained area is a1, B0, C0, and D0, it is determined that a1, B0, C0, and D0 are not the same group.
In step S230, the pixel coordinates of the center of each calibration point in the set of calibration base points and the pixel distance between the two nearest neighboring points are calculated.
And calculating the central point pixel coordinate of each calibration point in the set of calibration base points and calculating the pixel distance between every two adjacent and nearest calibration points in the set of calibration base points according to the central point pixel coordinate.
For example, a least squares ellipse fitting algorithm is used to calculate the center pixel coordinate of each calibration point in the set of calibration base points and calculate the pixel distance between each two nearest adjacent calibration points according to the center pixel coordinate.
The least square ellipse fitting algorithm is a relatively preferable image fitting method, does not limit the self-adaptive calibration method, and can obtain the same effect through other image fitting methods.
In step S240, the physical distance between each nearest two adjacent calibration points in the set of calibration base points is obtained.
And acquiring the physical distance corresponding to the code between each group of calibration base points according to the corresponding relationship between the code and the physical distance between each group of calibration base points on the pre-stored multi-scale calibration plate.
As shown in FIG. 4, in a set of base calibration points A0, B0, C0, and D0, the codes between A0B0, B0C0, C0D0, and A0D0 are the same, and the physical distances between the corresponding calibration points are the same. The encoding between A0B0 and A1B1 is different, corresponding to different physical distances.
In step S250, calibration parameters are calculated according to the acquired pixel distance and physical distance.
And calculating calibration parameters according to the acquired pixel distance, the physical distance and the spatial relationship between the imaging device and the multi-scale calibration plate.
In step S260, the calibration result is checked.
And (4) checking the calibration result, and calculating a calibration error according to the check result, for example, subtracting the check result from the real data to obtain the calibration error. Wherein, the real data is the physical distance between the target points of the object to be detected.
In step S270, whether the calibration result is within the system default range.
And judging whether the calibration result is in a default range of the system. And if the current time is within the default range of the system, finishing calibration. If the calibration error is greater than the default range of the system, the process proceeds to step S170 to re-calibrate.
The default range of the system is the default setting of the system, or is preset by the user.
In the above example, in the process of recalibration, in order to simplify the calibration process, it may be no longer determined whether the image data includes the multi-scale calibration plate and whether the included multi-scale calibration plate data is suitable for measurement, and the calculation in step S210 is directly performed after step S170.
Example 2
Fig. 4 shows a schematic structural diagram of a multi-scale calibration plate according to a second embodiment of the present invention.
The multi-scale calibration plate 12 includes: a calibration point 121 for calibrating the calibration parameters of the imaging device; code 122 for identifying a physical distance corresponding thereto, comprising: code start bit 123, code end bit 124, and code bits 125.
In this embodiment, the image data of the multi-scale calibration plate acquired by the imaging devices with three different views is taken as an example for explanation, wherein the view of the computer vision system can be any size, and is not limited to three in this embodiment. The calibration base points with the largest areas corresponding to different view field image data are different from each other, for example, in a view field Rect0, after filtering interference points, edge adhesion areas and non-connected areas, a set of calibration base points with the largest areas is obtained as A0, B0, C0 and D0; in the visual field Rect1, after filtering interference points, edge adhesion areas and non-communication areas, obtaining a group of calibration base points with the largest area, namely A1, B1, C1 and D1; in the visual field Rect2, after filtering the interference points, the edge adhesion area and the non-connection area, a group of calibration base points with the largest area is obtained as A2, B2, C2 and D2.
And the code 122 is arranged between every two adjacent calibration points of each group of calibration base points, the code corresponds to code information, and the code information and the physical distance have a corresponding relation and are used for identifying the physical distance between every two adjacent calibration points of each group of calibration base points.
For example, in the first set of base points A0, B0, C0, and D0, codes are provided between the index points A0B0, between the index points B0C0, between the index points C0D0, and between the index points A0D 0. In the second group of calibration base points A1, B1, C1 and D1, codes are arranged among the calibration points A1B1, B1C1, C1D1 and A1D 1. The first group of calibration base point codes are the same, namely, the codes between the calibration points A0B0, the codes between the calibration points B0C0, the codes between the calibration points C0D0 and the codes between the calibration points A0D0 have the same structure. The second set of base point codes is the same, i.e., codes between index points A1B1, codes between index points B1C1, codes between index points C1D1, and codes between index points A1D 1. The code between the first set of reference points is different from the code between the second set of reference points, i.e., the code between the calibration points A0B0 is different from the code between the calibration points A1B 1.
The code start bit 123 indicates a start scan code bit, the code end bit 124 indicates an end scan code, the code bit 125 has useful information about codes, and for example, codes between index points A0B0 are used as an example, SS0 indicates a start scan code, S00 to S07 indicate 8-bit code bits, codes corresponding to a physical distance between index points A0B0 are stored, and SE0 indicates an end of scan codes.
Fig. 5 is a schematic structural diagram illustrating encoding between two nearest neighboring calibration points in a multi-scale calibration board according to an embodiment of the present invention.
In a visual field Rect0, after filtering an interference point, an edge adhesion area and a non-connected area, obtaining a group of calibration base points with the largest area, namely A0, B0, C0 and D0, and obtaining the center point pixel coordinates and the radius R0 of the calibration points A0, B0, C0 and D0 by using an image processing algorithm. Since the codes of A0B0, B0C0, C0D0, and A0D0 are the same, and the physical distances between the corresponding index points are the same, this embodiment specifically describes a coding method of the multi-scale scaling board by taking the codes between index points A0B0 as an example. It should be noted that the present invention is not limited to the encoding method in the embodiment, and may also be in the form of two-dimensional codes, numbers, characters, geometric images, etc., and can be recognized in multiple directions and correspond to the same recognition result.
The 8-bit code is used as an example between A0B0 to identify the distance between the calibration points of each set of calibration base points in the horizontal direction and the vertical direction. Wherein, SS0 is the encoding start bit, SE0 is the encoding end bit, and S00-S07 are 8 bit encoding bits. The code bits are uniformly distributed relative to the index point A0B0, and the window width ratio of the code start bit and the code end bit is consistent and is distinguished from the aspect ratio of the code bits.
The center distance between index point a0 and index point B0 is L0, and the coded bit spacing distance between index point a0 and index point B0 is S0, which can be obtained by the following expression:
correspondingly, in the ith calibration base point, Si is:
and Li is the distance between AiBiCiDi and Ri is the radius of a group of calibration base points with the largest area in the ith view field.
For example, starting from a start position:
starting scanning along the A0B0 direction at the center point position + R0+0.5 × S0 of the index point A0;
and moving to the right for the first time by the step length S0 to reach the central position of the coding start bit SS0, acquiring the pixel gray value of the current position, and judging whether coding exists in the current position according to the gray value and a system preset threshold. It should be noted that the system preset threshold here is a system default gray value for determining whether a code exists, and if the obtained gray value is greater than the system preset threshold, it is determined that a code exists at the current position, and the code is used as a code start bit to continue scanning rightward; if the gray value is smaller than a system preset threshold value, exiting the scanning;
and moving to the right by the step size 2 × S0 for the second time, reaching the central position of the coded bits S00, and determining whether the code exists at the current position. If the current position has codes, the S00 codes that the code value is 1, otherwise, 0;
the third time, the right movement is carried out by the step size 2 × S0, and the center position of S01 is reached;
by analogy, 8-bit encoding between A0B0 is obtained by successively moving to the right by step 2 × S0 until scanning to the encoding end bit SE 0.
And acquiring the physical distance corresponding to the acquired 8-bit code according to the corresponding relation between the codes and the physical distances between each group of calibration base points on the pre-stored multi-scale calibration plate.
The corresponding relationship may be a corresponding relationship table or a formula function. As shown in the following table, the correspondence between the codes and the physical distances between the index points.
| Encoding | Physical distance (mm) |
| 11001101 | 100 |
| …… | …… |
| 11110100 | 20 |
For example, if the code between the index points is "11001101", the corresponding physical distance is 100 mm; if the code between the index points is "11110100", the corresponding physical distance is 20 mm.
Example 3
Fig. 6 shows a schematic structural diagram of a multi-scale calibration plate according to a third embodiment of the present invention.
In this embodiment, each calibration base point includes three identical calibration points 121 with orthogonal center-point connecting lines, and the calibration points 121 are circles filled with black. And the code 122 is arranged between two calibration points which are orthogonal to each other and form each group of calibration base points, and is used for identifying the physical distance between the two corresponding calibration points. The codes of each group of calibration base points are the same, and the codes of the groups of calibration base points are different from each other. For example, in the visual field Rect0, after filtering the interference points and the connected regions, a set of calibration base points with the largest area is obtained as A0, B0 and C0, wherein the codes between A0B0 and A0C0 are the same, and the physical distances between the corresponding calibration points are the same. The encoding between A0B0C0 and A1B1C1 in View Rect1 is different, corresponding to different physical distances. The encoding start bit 123 indicates the start scanning encoding bit, the encoding end bit 124 indicates the end of the encoding scanning, and the encoding bit 125 is provided with useful information for encoding. For example, taking the code between the index points A0B0 as an example, SS0 indicates the start scan code, S00 to S07 indicate 8-bit code bits, and a code corresponding to the physical distance between the index points A0B0 is stored, and SE0 indicates the end of the code scan.
According to the encoding method shown in fig. 4 in embodiment 3, the code between two calibration points in each orthogonal relationship between each set of calibration base points is obtained. And acquiring at least one physical distance corresponding to the acquired 8-bit code according to the corresponding relation between the pre-stored codes and the physical distances.
The corresponding relation can be a corresponding relation table or a formula function, etc. As shown in the following table, the correspondence between the codes and the physical distances between the index points.
| Encoding | Physical distance (mm) |
| 11001101 | 1，1，1.414 |
| …… | …… |
| 11110100 | 10，10，14.14 |
For example, if the code between the index points is "11001101", the corresponding physical distances are 1mm, 1mm, 1.414 mm; if the code between the index points is "11110100", the corresponding physical distances are 10mm, 10mm, 14.14 mm.
Because the graph formed by the connecting lines of the central points of each group of calibration base points is triangular, and the physical distances of two sides in an orthogonal relation are equal, the physical distance between every two adjacent closest calibration points in each group of calibration base points can be obtained according to the corresponding relation. For example, taking the code between the index points A0B0 in the view Rect0 as an example, if the code between the index points A0B0 is "11110100", the correspondence between the code and the physical distance indicates that the physical distance between the index points A0B0 is 10mm, the physical distance between the index points A0C0 is 10mm, and the physical distance between the index points B0C0 is 14.14 mm.
In the embodiments provided in the present application, it should be understood that the disclosed apparatus and method can be implemented in other ways. The apparatus embodiments described above are merely illustrative and, for example, the flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
In addition, each functional module or unit in each embodiment of the present invention may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.
The functions, if implemented in the form of software functional modules and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention or a part of the technical solution that contributes to the prior art in essence can be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a smart phone, a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention.
Claims (10)
1. The multi-scale calibration plate is characterized in that at least two groups of calibration base points and identifiable codes are arranged on the surface of the multi-scale calibration plate;
each group of calibration base points comprises at least three same calibration points which are distributed in an orthogonal relation;
defining a first group of calibration base points as a group of calibration base points close to the edge of the multi-scale calibration plate and a second group of calibration base points as a group of calibration base points adjacent to the first group of calibration base points; the area of a single calibration point of the first group of calibration base points is larger than the area of a corresponding calibration point in the second group of calibration base points;
the codes are arranged between at least one adjacent and nearest two calibration points in each group of calibration base points, and the codes of the groups of calibration base points are different from each other.
2. The multi-scale calibration plate according to claim 1, wherein the calibration points are circles, ellipses, squares, "+" shapes, "×" shapes or triangles with fill colors.
3. The multi-scale calibration plate according to claim 1, wherein the codes between each set of calibration base points can be identified in multiple directions and correspond to the same identification result.
4. The multi-scale calibration plate of claim 1, wherein the code is a bar code, a two-dimensional code, a number, a character, or a geometric figure.
5. The multi-scale calibration plate of claim 1, wherein the code corresponds to at least one physical distance.
6. The multi-scale calibration board of claim 1, wherein the encoding comprises an encoding start bit, an encoding bit and an encoding end bit.
7. The multi-scale calibration plate according to claim 1, wherein the multi-scale calibration plate is circular, elliptical, square, triangular or polygonal in shape.
8. The multi-scale calibration plate according to claim 1, wherein both sides of the multi-scale calibration plate are provided with the calibration points and the codes.
9. The multi-scale calibration plate according to claim 1, wherein the multi-scale calibration plate is made of a light-transmitting or backlight material.
10. An adaptive calibration system, comprising:
the multi-scale calibration plate comprises at least two groups of calibration base points and identifiable codes, wherein each group of calibration base points comprises at least three calibration points which are the same and are distributed in an orthogonal relation; defining a first group of calibration base points as a group of calibration base points close to the edge of the multi-scale calibration plate and a second group of calibration base points as a group of calibration base points adjacent to the first group of calibration base points; the area of a single calibration point of the first group of calibration base points is larger than the area of a corresponding calibration point in the second group of calibration base points; the codes are arranged between at least one adjacent and nearest two calibration points in each group of calibration base points, and the codes of the groups of calibration base points are different from each other;
and the imaging device is used for acquiring the image data of the multi-scale calibration plate and processing the image data to finish the calibration process.
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| US11861446B2 (en) * | 2018-07-24 | 2024-01-02 | Illinois Tool Works Inc. | Method and apparatus for using encoded information for material preparation and analysis equipment |
| CN109151456B (en) * | 2018-08-17 | 2020-05-05 | 上海交通大学 | Calibration plate for focusing sheet laser plane of high-speed camera and focusing method |
| CN109443697B (en) * | 2018-09-29 | 2021-10-15 | 歌尔光学科技有限公司 | Optical center testing method, device, system and equipment |
| CN110986846B (en) * | 2019-12-10 | 2022-04-29 | 中国计量科学研究院 | Multi-quantity metering standard device and preparation method thereof |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011014340A2 (en) * | 2009-07-31 | 2011-02-03 | Lightcraft Technology, Llc | Methods and systems for calibrating an adjustable lens |
| CN203217624U (en) * | 2013-05-04 | 2013-09-25 | 长春工业大学 | Novel checkerboarded calibration target |
| CN104217429A (en) * | 2014-08-25 | 2014-12-17 | 太仓中科信息技术研究院 | Design and detection method of camera calibration board |
| CN105405126A (en) * | 2015-10-27 | 2016-03-16 | 大连理工大学 | Multi-scale air-ground parameter automatic calibration method based on monocular vision system |
| CN106780625A (en) * | 2016-12-19 | 2017-05-31 | 南京天祥智能设备科技有限公司 | Many mesh camera calibration devices |
| CN106774386A (en) * | 2016-12-06 | 2017-05-31 | 杭州灵目科技有限公司 | Unmanned plane vision guided navigation landing system based on multiple dimensioned marker |
| CN207882968U (en) * | 2017-12-27 | 2018-09-18 | 苏州多比特软件科技有限公司 | Multiple dimensioned scaling board |
-
2017
- 2017-12-27 CN CN201711440906.5A patent/CN107945237B/en not_active Expired - Fee Related
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011014340A2 (en) * | 2009-07-31 | 2011-02-03 | Lightcraft Technology, Llc | Methods and systems for calibrating an adjustable lens |
| CN203217624U (en) * | 2013-05-04 | 2013-09-25 | 长春工业大学 | Novel checkerboarded calibration target |
| CN104217429A (en) * | 2014-08-25 | 2014-12-17 | 太仓中科信息技术研究院 | Design and detection method of camera calibration board |
| CN105405126A (en) * | 2015-10-27 | 2016-03-16 | 大连理工大学 | Multi-scale air-ground parameter automatic calibration method based on monocular vision system |
| CN106774386A (en) * | 2016-12-06 | 2017-05-31 | 杭州灵目科技有限公司 | Unmanned plane vision guided navigation landing system based on multiple dimensioned marker |
| CN106780625A (en) * | 2016-12-19 | 2017-05-31 | 南京天祥智能设备科技有限公司 | Many mesh camera calibration devices |
| CN207882968U (en) * | 2017-12-27 | 2018-09-18 | 苏州多比特软件科技有限公司 | Multiple dimensioned scaling board |
Non-Patent Citations (1)
| Title |
|---|
| 一种基于圆形标志点的摄像机标定方法;周艳青等;《内蒙古农业大学学报》;20140327;第35卷(第1期);第155-159页 * |
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